Enter pour and weather details
Sample scenarios for garden concrete work
| Scenario | Temp (°C) | RH (%) | Wind (km/h) | Mix | Method | Thickness (cm) | Expected window |
|---|---|---|---|---|---|---|---|
| Garden path, mild morning | 20 | 70 | 5 | Standard | Broom | 10 | Moderate and forgiving |
| Patio in full sun | 32 | 45 | 18 | Hot-weather adjusted | Trowel | 10 | Shorter; plan extra hands |
| Stepping stones, cool shade | 12 | 85 | 3 | Cold-weather adjusted | Broom | 8 | Longer; protect overnight |
| Decorative stamped slab | 24 | 60 | 10 | Fly ash blend | Stamped | 12 | Watch timing; uniform texture |
How the time window is estimated
The calculator starts with a baseline initial set time at 20°C, then applies multipliers for temperature, mix type, thickness, humidity, wind, sun exposure, and admixtures.
Field workflow for garden pours
- Enter the pour start time and local weather values.
- Select mix type, finish method, and any admixture choice.
- Enter slab thickness, area, and crew size.
- Press Calculate to see the finishing window above.
- Start finishing near the suggested start time shown.
- Begin curing actions immediately after finishing completes.
Why finish timing matters
Concrete for garden slabs behaves differently from soil work because it changes quickly after placing. Finishing too early traps bleed water and weakens the surface. Finishing too late forces extra troweling pressure and can leave burn marks, delamination, or poor broom texture. This calculator turns jobsite conditions into a working window, so your planned edging, slopes, and joints stay crisp.
Reading the weather inputs
Air temperature influences hydration speed, while wind, sun, and humidity control evaporation at the top layer. High wind and low humidity can stiffen the surface before the slab gains enough strength, increasing plastic shrinkage cracking risk. Enter site values near the pour, not a distant forecast point. If you know concrete temperature at discharge, use it, because it is the strongest driver of set time.
Mix and admixture impacts
Different mixes develop set at different rates. High-early mixes shorten the schedule, while fly ash or slag blends often extend workable time. Retarders can preserve finishing flexibility in hot weather, and accelerators help in cool mornings, but both must match the supplier’s dosage guidance. The calculator models these effects as multipliers, helping you compare scenarios before you commit to a delivery slot.
Crew planning for small pours
Garden pours often seem simple, yet stamped textures and corners reduce productivity. The tool estimates finishing duration from area, method, and crew size, then checks whether completion fits inside the window. If the “complete by” time pushes past the window end, reduce the pour size, stage tools earlier, or add hands. This planning step protects surface quality and avoids rushed edging.
Curing steps after finishing
Once finishing ends, curing should begin immediately to retain moisture and control temperature swings. Use curing compound, wet coverings, or plastic sheeting, and protect edges from drying winds. For garden work, keep foot traffic off early and delay heavy planters until strength develops. The calculator’s curing start reminder aligns your crew’s cleanup with curing actions, improving durability and reducing dusting.
1) When should I start broom finishing?
Start when bleed water is gone and the surface supports light pressure without tearing. Use the window start and suggested start as guidance, then confirm with a fingertip or knee test on a noncritical edge.
2) Does slab thickness affect the finish window?
Yes. Thicker sections can bleed longer and hold heat, shifting timing slightly. Enter thickness so the calculator can adjust the estimated set time and keep the window realistic for garden pads and paths.
3) Should I enter concrete temperature or air temperature?
If you know the concrete temperature at discharge, use it. If not, use air temperature near the slab. Concrete temperature usually predicts set time better than forecast air temperature alone.
4) What if my “complete by” time is after window end?
Reduce pour size, add finishers, or choose a simpler finish method. You can also plan earlier placement, shade the slab, or use a retarder in hot weather, following supplier guidance.
5) How do accelerators and retarders change the estimate?
Accelerators shorten the set time and move the window earlier. Retarders lengthen the set time and expand workable time. The strength slider applies a percentage adjustment so you can compare “light” versus “strong” dosing scenarios.
6) When should curing begin after finishing?
Begin curing immediately after the surface finish is complete. Apply curing compound, cover with wet burlap, or use plastic sheeting, and protect edges from wind. Early curing improves durability and reduces dusting.